Known in the prior art are military ballistic fuzes having a tuning fork crystal time base These conventional military ballistic time fuzes traditionally employ expensive and sophisticated methods to precisely control the detonate time of the device. The crystal controlled oscillator is a component of each fuze. Said crystals, which are fragile, must be capable of withstanding the extreme impact forces imparted to them during the ejection of the fuze from the firing device, which in most cases are in the thousands of g range. It is costly to provide such capability to said crystals. Since these crystals have the disadvantage of being very costly, they are in some situations cost prohibitive when military ballistic fuzes are manufactured in the hundred of thousands quantities.
Normally a conventional military ballistic time fuze system employs the crystal controlled oscillator regardless of expense, since until the advent of this invention no other method has been devised to eliminate the crystal and still maintain the required time accuracy demanded in military time fuze applications. Said crystals must withstand all the rigors of the military environment including temperature extremes, shock and vibration, etc. Since the crystal is manufactured of quartz it is a fragile device, and even though quartz crystals can be made to withstand the rigors of ballistic impacts during ejection, it is expensive to do so, and common practice usually dictates, that to insure total reliability, redundancy be employed. Redundancy in this case means duplication of the crystal and associated circuitry. Naturally, redundancy automatically further increases cost.
Prior art fuze programmers have used a contact system or plug in arrangement to transfer signals between programmer and fuze, and accordingly have the problem of sealing the contacts and keeping them clean in the field. Prior art fuze devices have set mission parameters with a thumbwheel arrangement or some mechanical arrangement of ring switches about the nose cone of the fuze. Such arrangements are disadvantageous because of difficulty of sealing the switches while still maintaining low cost. There are also problems with setting the switches with arctic gloves and NBC clothing.
Cost factors are major considerations in military budgets, especially when small unit costs on an individual unit are multiplied by hundreds of thousands or even millions of times. It therefore becomes important to consider other ways to achieve cost effectiveness while maintaining precise control of the fuze time. Hence the need for the invention.